/// <summary>
/// Gets material batches, possibly filtered.
/// </summary>
/// <param name="materialId">The ID of a material to filter with.</param>
/// <param name="siteId">The ID of a storage site to filter with.</param>
/// <returns>Returns all matching batches.</returns>
public IEnumerable <MaterialBatch> GetMaterialBatches(int?materialId = null, Guid?siteId = null)
{
IEnumerable <MaterialBatch> materialBatches = MaterialBatchRepository.GetMaterialBatches(materialId, siteId);
return(materialBatches);
}